The curfew restricts military personnel to the base, a personal home or hotel between 11 p.m. and 5 a.m.

Police in Okinawa identified the detained sailors as U.S. Navy Seaman Christopher Daniel Browning and Petty Officer Skyler Dozierwalker of Naval Air Station Joint Reserve Base Fort Worth in Texas. The two men, both 23, are alleged to have raped a Japanese woman early Tuesday, leaving her with a neck injury, police said. They were taken into custody later that day.

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The incident has prompted a women's group in Okinawa to call for more restrictions on what U.S. military personnel can do when off-base.

The issue of violent crimes, especially rapes, by U.S. troops in Japan has divided the two countries for decades. It came to a peak in 1995 when a U.S. sailor and two U.S. Marines were convicted of raping a 12-year-old girl. Tens of thousands of Okinawans took to the streets at the time demanding that the United States leave the island south of Japan's main islands.

In that case, the U.S. military at first refused to turn the suspects over to Japanese authorities. But in the most recent case, the suspects were in Japanese custody almost immediately.

The alleged attack took place two months after a U.S. Marine was arrested, accused of assaulting and molesting a woman in Naha, the capital of Okinawa.

Relations between the U.S. military and the people of Okinawa have already been stressed in recent months over the U.S. Marine Corps' deployment of MV-22 Osprey tilt-rotor aircraft to a base on the island. Some Okinawa residents are concerned because the Osprey has had a reputation for crashing.

The Okinawan community has long been against the presence of the U.S. military, which recently announced that thousands of Marines will be moved to a base in Guam.